Tutorial: Altering the Waist of Men's Trousers

Of all the alterations for men's trousers, the waist is the quickest and arguably the most important. If the waist size isn't correct, then it can effect every other aspect of the fit of the garment. So, here is how it's done.

1. Remove the center back belt loop.

2. Lift up the center back section of the waistband and remove the stitching holding the waistband in place (usually two short rows).

3. Pin the bottom and the top of the waist band.

4. Double check from the outside that each seam of the waistband is lined up perfectly.

5. Mark your stitching line.

You will mark half of the total amount that needs to be adjusted. For example this pair needs to be made smaller by 1", so it is marked 1/2" from the original stitching.

If you need to make the trousers smaller, your stitching line will be on the left side of the original stitching.
If you need to make the trousers larger, your stitching line will be on the right side of the original stitching.

The line through the waistband should be exactly parallel with the original stitching. After you're past the waistband, taper it in  gently to meet up again with the original stitching.

6. Stitch down the marked line twice. A double stitch ensures security.

7. Remove the original stitching.

If this is the first time the trousers have been altered, the original stitching will most likely be a chain stitch. You can just clip it on one end and pull the whole thing out in about three seconds. 

8.. Open the new seam and fold the waistband back down. Pin through all the layers keeping the pin right in the center.

9. Pull out one inside section. Fold up the end corner and tack into place. Repeat on the other side.
If you're increasing the size of the trousers as much as possible you won't have end corners to fold up and tack. Instead, just fold the waistband down and tack vertically along the back seam of the waistband.

10. Reattach the belt loop.

11. Press the new seam.


TIPS

-Standard sized trousers shouldn't be taken in more than about 2",  otherwise the back pockets can get too close together.

-Don't cut out the extra fabric if the trousers will ever need to be altered again.